There is a national interest in the discovery of alternative sources of fuels and chemicals, other than from petroleum resources. As the public discussion concerning the availability of petroleum resources and the need for alternative sources continues, government mandates will require fuel range hydrocarbons to include, at least in part, hydrocarbons derived from sources besides petroleum. As such, there is a need to develop alternative sources for hydrocarbons useful for producing fuels and chemicals.
One possible alternative source of hydrocarbons for producing fuels and chemicals is the natural carbon found in plants and animals, such as for example, oils and fats. These so-called “natural” carbon resources (or renewable hydrocarbons) are widely available, and remain a target alternative source for the production of hydrocarbons. For example, it is known that oils and fats has been successfully hydrotreated to produce hydrocarbons/fuel range hydrocarbons which is also called “Renewable fuel” such as renewable diesel fuels.
Compared to vegetable oil or animal fat, there are many cheap low-cost and waste by-products of the food industry that are readily available in the market. For example, acidulated soapstock is a by-product of soybean oil degumming with a very high fatty acid content (>88%) and could be a potential feedstock for renewable diesel production. However, the product suffers from high metals and acid content which makes it difficult for direct hydroprocessing.
High acid content has been addressed by converting the fatty acids into esters with the use of alkaline catalysts and methanol as a solvent. However, esterification reactions are equilibrium processes that require vast excess of solvent. Though fatty acid methyl esters are directly being used as bio-diesel in the market, they suffer from stability and quality issues.
As such, development of a new pretreatment methodology that would solve the issue of high acid content present in low-cost renewable feedstock and renders such feedstock suitable for hydroprocessing to renewable hydrocarbon could be a significant contribution to the art and to the economy.